Ball-grinding mill.



e. NEWCOMER.

- BA'LL GRINDING MILL'. 7 APPLICATION FILED APR-22, 1215.

Patented. Apr.- 4, 1916.

UNITED STATES PATENT: OFFICE.

GEORGE 1vr. NEwcoMER, or NEW YORK, N. Y., AssIeNoR ro r. L. meant: c'ol, anew} YORK, N. Y., A CORPORATION OF, NEW JERsnYQ BALL-GRINDING MILL."

The cylinders of ball grinding mills are commonly provided, both as to their end walls and their circumferential walls, with liner plates of steel which are detachably se-' cured in place, in order that they may be removed and replacedreadily when worn out. Such-liner plates are subjected, in the operation of a mill, to a continuous and severe pounding, which action, like that of.

peening hammers, results in a spreading of the metal on the working-face and an elon-. gation of each plate in all directions. If the boltsby which the plates are secured to the shell do not give way the plates themselves are distorted, bulging inwardly intothe mill. times distorted. Most frequently, however, the bolts by which the plates are secured to the "walls of the mill are broken. In any case permanent injury to the mill itself usually results and always more or less loss. The peening of the plates cannot be prevented.

It is therefore the object'of this invention to prevent the injurious results which follow from the peening of the plates. In accordance with the invention the plates are out either part way through or entirely through, that is, are grooved or slotted, along the lines in which the greatest strains are developed by the peening. In this manner space is provided for the flowing of the metal under the peening action and the distortion of the plates, the distortion of the shell walls of the mill, and the rupture of the bolts are entirely prevented.

The invention will be more fully explained hereinafter with reference to the accompanying drawing in which it 1s illustrated and in which--- Figure l is a view in transverse sectlon, on the plane indicated by the line 1 -1 of Fi 2, of aball grinding mill equipped wlth the invention. Fig. 2 is a. longitudinal sec- Sp'ecification of Letters Patent.

the line 7- -7 of Fig. 5.

.walls also. bodies and the materialtok be ground would The walls of the mill are-also some-- Patented $111 231, 1916.

-App1icationfi1edAprii22,1915...Seria1No.23,004.

tion of the same on the the line 22 of Fig. l. F i g. 3 i s ,a. detail view of one sector of the end, lining, .Figi 1s a sect1on on the plane., i1 di 1 b yfthealine l-l of Fig. 3, showing. the end ,walljofi themillas well as the endJifning. IFig 5.is a -deta1l new 111' sect1on,.on,;a, plane .co rre-J sponding to that of Fig. I -but larger scale. Fig. 6 1s a face view, ofoneof'the 1.

circumferential liner plates Fig. 7. is, a de tall new of one of the clrcuniferentialliner plates in section on the plane indicatedby Except as pointed out grinding mill in which the invention is indi-. cated as embodied, may be,of ,o1 'dinary" construction, comprising a cylinder a with end plates band a supporting shaft-,0; Such mill is chargedwith grinding bodies, such as steel balls, and with thef n aterialto-,be,, ground and is then rotated. Asthe heavy. grinding bodies tumble about inthez'mill they strike the inner circumferential walls with heay'yblowsand to soine extent the end The. actionpf, the grinding quickly wear through the shell walls, both circumferential and end, if, they werev not,

protected. Therefore they are protected by heavy steel plates which are detachably secured in place so that they may be removed and replaced when they are broken or worn out. The circumferential liner plates are usually lapped so as to form steps on the. inner face of the wall to assist in the proper movement of the grinding bodies and material to be ground, but the end plates usually present substantially plane surfaces. In the drawing the end liner plates are shown at (Z d and the circumferential liner plates at e. I

'The end liner plates are usually formed insegments which extend from the central opening to the circumference in one piece, each segment being secured by bolts to the end plate 6. In the present case, however, each'segment is formed of separate plates, as d and d, that is to say, each segment is cutentirely through, as at (Z in a line concentric with the cylinder. Furthermore, each plate, which is secured to the end wall Z) by several bolts, as at (P, is out, either. part way through or entirely through, as at d, on the lines in which the greatest strains are developed by the peening action.

These lines of greatest strain, in such end' the plates through the spacing pieces f, and

through slots e' in the thinner ends of the plates. The slots 6 inthe thinner ends of the plates permit the spreading of the plates in a circumferential direction under the peening action, without distortion either of the plates or of the shell. To prevent, however, the injurious efiect of the. peening action in a longitudinal direction with 're-' spect to the axis of the'mill, the plate is cut, as at 6 in circumferential lines between the bolts by which the plates aresecured in place, these being the lines in which the greatest strains are developed by the peemng action.

The end plates-are shown as cut entirely through on the lines of the greatest strains while the circumferential plates are shown as cut only'part way through. By the cutting all the way through in lines of limited extent as shown in Figs. 3 and 4, the plates are not weakened to such an extent as to make them liable to breakage. On the other hand, when the plates are out only part way through, as indicated, in Figs. 5,.

6 and 7, the result mainly desired is accomplished, that is, the strains are relieved while the plate is new and heavy, and when vthe plate is' worn to the bottom of the cuts it has then lost its strength to such an extent that it is not likely to over-strain the bolts W or to distort the walls of the mill.

I claim as my invention 1. In a ball grinding mill, the combination with the shell of the mill, comprising a circumferential wall and end plates, of liner plates secured to one of said end plates, comprising segments spaced from one another along a line concentric with the axis of the mill, such-liner plates being slotted also in radial lines to relieve the strains produced by the peening action on such plates.

2. Ina ball grinding mill, the combination with the shell of the mill comprisinga circumferential wall and end plates, of

liner plates secured to one of said end plates by bolts and comprising segments spaced from one another along a line concentric.v

with the axis of the mill and between circular series of saidbolts, such liner plates. being slotted also in radial lines extending from proximate edges of the'segments between said bolts of the circular series to relieve the strains produced by the peening action on such plates. This specification signed this 21st April A. D., 1915.

' GEORGE M. XEVCOMER.

day of 

